picatinny base thickness?

Can anyone tell the thickness of some of picatinny bases? Badger, Tps , Farrell so I can figure the right size rings to put the scope as low as I can. I want to mount a Mk-4 6.5-20x50 on a rem 700 sendero 7stw for some longrange shooting. Where is the best place too order the Tps or the Badger rings & bases to get the best price?